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Nervous system disruption and concomitant behavioral abnormality in early hatched pufferfish larvae exposed to heavy oil
2012
Kawaguchi, Masahumi | Sugahara, Yuki | Watanabe, Tomoe | Irie, Kouta | Ishida, Minoru | Kurokawa, Daisuke | Kitamura, Shin-Ichi | Takata, Hiromi | Handoh, Itsuki C. | Nakayama, Kei | Murakami, Yasunori
BACKGROUND AND OBJECTIVE: Spills of heavy oil (HO) over the oceans have been proven to have an adverse effect on marine life. It has been hypothesized that exposure of early larvae of sinking eggs to HO leads largely to normal morphology, whereas abnormal organization of the developing neural scaffold is likely to be found. HO-induced disruption of the nervous system, which controls animal behavior, may in turn cause abnormalities in the swimming behavior of hatched larvae. To clarify the toxicological effects of HO, we performed exposure experiments and morphological and behavioral analyses in pufferfish (Takifugu rubripes) larvae. EXPERIMENTAL PROCEDURE: Fertilized eggs of pufferfish were exposed to 50 mg/L of HO for 8 days and transferred to fresh seawater before hatching. The hatched larvae were observed for their swimming behavior, morphological appearance, and construction of muscles and nervous system. RESULTS AND DISCUSSION: In HO-exposed larvae, we did not detect any anomaly of body morphology. However, they showed an abnormal swimming pattern and disorganized midbrain, a higher center controlling movement. Our results suggest that HO-exposed fishes suffer developmental disorder of the brain that triggers an abnormal swimming behavior and that HO may be selectively toxic to the brain and cause physical disability throughout the life span of these fishes.
Afficher plus [+] Moins [-]Chemotaxis to atrazine and detection of a xenobiotic catabolic plasmid in Arthrobacter sp. DNS10
2012
Zhang, Ying | Zhao, Jiang | Cao, Bo | Hu, Miao | Wang, Zhigang | Dong, Xiaonan
INTRODUCTION: A plasmid named pDNS10 was detected from an atrazine-degrading strain Arthrobacter sp. DNS10 which has been isolated previously in our laboratory. MATERIALS AND METHODS: In this paper, a special plasmid-detecting method and drop assays experiments were mainly used to achieve research goals. RESULTS AND DISCUSSION: pDNS10 exhibited an excellent stability because it also could be detected even when the strain DNS10 has been subcultured under nonselective conditions for eight times. Over a 48-h incubation period, the OD₆₀₀ of samples inoculated with strain DNS10 and strain DNS10-ST (both of them contained pDNS10) were 0.31 ± 0.042 and 0.305 ± 0.034, respectively ,whereas the OD₆₀₀ of samples inoculated strain without pDNS10 (strain DNS10-PE) was only 0.138 ± 0.018. No atrazine was detected in the inoculated strain DNS10 and strain DNS10-ST samples at this period. Contrarily, the atrazine-degrading rate of strain DNS10-PE was only 5.23 ± 0.71%. Furthermore, both the two types of strains containing pDNS10 confirmed the presence of known degrading genes such as trzN, atzB, and atzC. It suggests that pDNS10 is an atrazine catabolic plasmid. In drop assays experiments, the wild-type strain DNS10 cells were chemotactically attracted to atrazine, whereas strain DNS10-PE showed no chemotaxis to atrazine and hydroxyatrazine. There was some relationship between atrazine degradation and the chemotactic response towards atrazine in strain DNS10. CONCLUSIONS: The biochemical characteristics of pDNS10 and the chemotaxis characteristics of strain DNS10 could help us in better understanding of the mechanism of atrazine degradation by strain DNS10.
Afficher plus [+] Moins [-]New developments on emerging organic pollutants in the atmosphere
2012
Balducci, Catia | Perilli, Mattia | Romagnoli, Paola | Cecinato, Angelo
BACKGROUND: The continuous progress in analytical techniques has improved the capability of detecting chemicals and recognizing new substances and extended the list of detectable contaminants widespread in all environmental compartments by human activities. Most concern is focused on water contamination by emerging compounds. By contrast, scarce attention is paid to the atmospheric sector, which in most cases represents the pathway of diffusion at local or global scale. Information concerning a list of organic pollutants is provided in this paper. METHODS: The volatile methyl tert-butyl ether and siloxanes are taken as examples of information insufficient with regard to the potential risk induced by diffusion in the atmosphere. Illicit drugs, whose presence in the air was ascertained although by far unexpected, are considered to stress the needs of investigating not solely the environmental compartments where toxic substances are suspected to display their major influence. Finally, the identification of two recognized emerging contaminants, i.e., tris(2-chloroisopropyl) phosphate and N,N-diethyl-m-toluamide, in aerosols originally run to characterize other target compounds is presented with the purpose of underlining the wide diffusion of the organic emerging contaminants in the environment.
Afficher plus [+] Moins [-]Optimization of electrocoagulation process for the simultaneous removal of mercury, lead, and nickel from contaminated water
2012
Vasudevan, Subramanyan | Lakshmi, Jothinathan | Sozhan, Ganapathi
PURPOSE AND AIM: The present study provides an optimization of electrocoagulation process for the simultaneous removal of heavy metals such as mercury, lead, and nickel from water. In doing so, the thermodynamic, adsorption isotherm and kinetic studies were also carried out. MATERIALS AND METHODS: Magnesium alloy, magnesium, aluminum, and mild steel sheet of size 2 dm² were used as anode and galvanized iron as cathode. To optimize the maximum removal efficiency, different parameters like effect of initial concentration, effect of temperature, pH, and effect of current density were studied. Mercury-, lead-, and nickel-adsorbed magnesium hydroxide coagulant was characterized by SEM and EDAX. RESULTS: The results showed that the maximum removal efficiency was achieved for mercury, lead, and nickel with magnesium alloy as anode and galvanized iron as cathode at a current density of 0.15 Å/dm² and pH of 7.0. The adsorption of mercury, lead, and nickel are preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The adsorption process follows second-order kinetics. Temperature studies showed that adsorption was endothermic and spontaneous in nature. CONCLUSIONS: The magnesium hydroxide generated in the cell removes the heavy metals present in the water and reduces to a permissible level, making it drinkable.
Afficher plus [+] Moins [-]Organochlorine pesticides and polychlorinated biphenyls in air and soil across Azerbaijan
2012
Aliyeva, Gulchohra | Kurkova, Romana | Hovorkova, Ivana | Klánová, Jana | Halsall, Crispin
Concentrations of selected organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are reported in air and surface soil in an extensive spatial survey across Azerbaijan, a country bordering the Caspian Sea with a history of OCP production and extensive use. Polyurethane foam disc passive air samplers (PAS) were deployed during October–November 2008 with soil samples collected in July 2009. Levels of Σ7PCB in ambient air were generally low (mean of 0.046 ng m−3, n = 13) and comparable to concentrations reported in countries within Eastern Europe and similar to or lower than concentrations reported in urban air in the UK and other western countries. Surprisingly, PCB concentrations in rural/background soil fell below the method detection limits at most sites, although concentrations were 0.209 and 0.071 ng Σ7PCB g−1 dry weight (dw) for two urban sites, again comparable to PCB levels measured at background sites in Europe. Levels of α-HCH, β-HCH, γ-HCH and p,p′-DDT/E were elevated in ambient air across Azerbaijan in comparison to PAS-derived concentrations reported elsewhere, with concentrations of α-HCH in air ranging from 0.085 to 2.699 ng m−3 and p,p′-DDE, 0.037–2.290 ng m−3. High concentrations of OCPs occurred at several of the urban sites and at sites in proximity to old pesticide storage facilities with concentrations in soil >0.1 μg g−1 dw for p,p′-DDE and p,p′-DDT at several sites. The ratio of p,p′-DDT/p,p′-DDE was close to unity in the soil at these sites, but elsewhere, the ratio was <1, indicating a weathered DDT pattern, which was also reflected in the air at all sites. A fugacity approach revealed the strong likelihood of net soil-to-air transfer at the majority of sites for all OCPs. The calculated annual fluxes or loading to the atmosphere from a rural/agricultural area (representing land as vineyards and cotton cultivation) were estimated to be on the order of ≈10–100 kg year−1 for the HCH isomers (including the β -isomer) and p,p′-DDE. The high levels of OCPs in soils, particularly in the vicinity of obsolete-pesticide storage facilities and at select urban sites are of concern and warrant regular monitoring activities and the development of containment or mitigation strategies.
Afficher plus [+] Moins [-]Multivariate analysis of mineral constituents of edible Parasol Mushroom (Macrolepiota procera) and soils beneath fruiting bodies collected from Northern Poland
2012
Gucia, Magdalena | Jarzyńska, Grażyna | Rafał, Elżbieta | Roszak, Magdalena | Kojta, Anna K. | Osiej, Irena | Falandysz, Jerzy
Caps and stipes of 141 fruiting bodies of Parasol Mushroom (Macrolepiota procera) and surface layer of soils collected from 11 spatially distant and background (pristine) areas in Northern Poland were analyzed for Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, and Zn by inductively coupled plasma optical emission spectroscopy and cold vapor atomic absorption spectroscopy. In terms of bioconcentration and bioexclusion concept, K, Ag, Cu, Rb, and P were highly bioconcentrated in caps, and their bioconcentration factor values varied for the 11 sites between 120 and 500—67–420, 70–220, 10–170, and 45–100, respectively. Cd, Zn, Mg, and Na showed bioconcentration factors (BCFs) between 3.3 and 36, 3.7–15, 0.92–6.3, and 1.4–44 while Al, Ba, Ca, Co, Cr, Mn, Ni, Pb, and Sr were excluded (BCF < 1). The Parasol Mushroom is a species harvested in the wild, and its caps are of unique taste and can contain a spectrum of essential and hazardous mineral compounds accumulated at elevated concentrations, even if collected at the background (pristine) areas. These elevated mineral concentrations of the caps are due to the efficient bioconcentration potential of the species (K, Ag, Cu, Rb, P, Cd, Zn, Mg, and Na) and abundance in the soil substrates (Al, Ca, Fe, Mn). The estimated intake rates of Cd, Hg, and Pb contained in Parasol Mushroom’s caps show a cause for concern associated with these metals resulting from the consumption of between 300- and 500-g caps daily, on a frequent basis in the mushrooming season.
Afficher plus [+] Moins [-]Transition metal-modified zinc oxides for UV and visible light photocatalysis
2012
Bloh, J. Z. | Dillert, R. | Bahnemann, D. W.
In order to use photocatalysis with solar light, finding more active and especially visible light active photocatalysts is a very important challenge. Also, studies of these photocatalysts should employ a standardized test procedure so that their results can be accurately compared and evaluated with one another. A systematic study of transition metal-modified zinc oxide was conducted to determine whether they are suitable as visible light photocatalysts. The photocatalytic activity of ZnO modified with eight different transition metals (Cu, Co, Fe, Mn, Ni, Ru, Ti, Zr) in three different concentrations (0.01, 0.1, and 1 at.%) was investigated under irradiation with UV as well as with visible light. The employed activity test is the gas-phase degradation of acetaldehyde as described by the ISO standard 22197-2. The results suggest that the UV activity can be improved with almost any modification element and that there exists an optimal modification ratio at about 0.1 at.%. Additionally, Mn- and Ru-modified ZnO display visible light activity. Especially the Ru-modified ZnO is highly active and surpasses the visible light activity of all studied titania standards. These findings suggest that modified zinc oxides may be a viable alternative to titanium dioxide-based catalysts for visible light photocatalysis. Eventually, possible underlying mechanisms are proposed and discussed.
Afficher plus [+] Moins [-]Molecular cloning and expression of novel metallothionein (MT) gene in the polychaete Perinereis nuntia exposed to metals
2012
Won, Eun-Ji | Rhee, Jae-Sung | Ra, Kongtae | Kim, Kyung-Tae | Au, Doris W. T. | Shin, Kyung-Hoon | Lee, Jae-seong
To report a novel metallothionein (MT) gene and evaluate its potency as a biomarker, we clone this MT gene and measured the expression levels in the metal-exposed polychaete Perinereis nuntia. Accumulated metal contents and metallothionein-like proteins (MTLPs), which have been recognized as potential biomarkers, were compared with the relative mRNA expressions of the MT gene of P. nuntia (Pn-MT). In addition, the metal-binding affinity was estimated by recombinant Pn-MT protein. Pn-MT having high cysteine residues with three metal response elements in the promoter region closely clusters with those of other invertebrates. The accumulation patterns of metals were dependent on the exposure times in lead (Pb), cadmium (Cd), and copper (Cu) exposure. Particularly, both MTLP levels and relative mRNA expressions of MT were increased with accumulated metal contents and exposure time in P. nuntia exposed to Pb and Cd. There was no significant modulation of the Pn-MT gene in polychaetes exposed to Zn and As. However, the metal-binding ability of the recombinant Pn-MT protein provides a clear evidence for a high affinity of MT to several metal elements. These results suggest that Pn-MT would play an important role in the detoxification and/or sequestration of specific metals (e.g., Pb and Cd) in P. nuntia and have potential as a molecular biomarker in the monitoring of the marine environment using a polychaete.
Afficher plus [+] Moins [-]Wavelet transform-based artificial neural networks (WT-ANN) in PM10 pollution level estimation, based on circular variables
2012
Shekarrizfard, Maryam | Karimi-Jashni, A. | Hadad, K.
INTRODUCTION: In this paper, a novel method in the estimation and prediction of PM10 is introduced using wavelet transform-based artificial neural networks (WT-ANN). DISCUSSION: First, the application of wavelet transform, selected for its temporal shift properties and multiresolution analysis characteristics enabling it to reduce disturbing perturbations in input training set data, is presented. Afterward, the circular statistical indices which are used in this method are formally introduced in order to investigate the relation between PM10 levels and circular meteorological variables. Then, the results of the simulation of PM10 based on WT-ANN by use of MATLAB software are discussed. The results of the above-mentioned simulation show an enhanced accuracy and speed in PM10 estimation/prediction and a high degree of robustness compared with traditional ANN models.
Afficher plus [+] Moins [-]Sampling and analytical methods for assessing the levels of organic pollutants in the atmosphere: PAH, phthalates and psychotropic substances: a short review
2012
Cecinato, Angelo | Balducci, Catia | Mastroianni, Daniele | Perilli, Mattia
This short review presents the procedures used to monitor PAHs, phthalates and psychotropic substances in the air, and the results of some measurements made in Italy and abroad. Organic contaminants are characterized by a variety of physical and chemical properties, including aggregation phase, concentration level, and life time. This variety widens the spectrum of procedures developed to assess their occurrence in the environment and biota, but prevents the complete speciation of the “organic fraction” of air, waters and particulates, and attention is paid to a few substances. The progress in health sciences stimulates the concern on contaminants and the development of new instrumental apparatuses and methods; new chemicals are continuously identified or recognized as capable of injuring the environment and organisms. Persistent organic pollutants and persistent biologically active toxicants are subject to regulation and extensively measured by means of standard procedures. For instance, polycyclic aromatic hydrocarbons, polychlorobiphenyls and polychlorodibenzodioxins are recovered from air through phase partition, thermal desorption or solvent extraction, then separated and detected through GC–MS or HPLC–MS procedures. By contrast, dedicated methods must be still optimized to monitor candidates or possible candidates as emerging organic pollutants, e.g. phthalates, flame retardants and perfluoroalkanes. Also, psychotropic substances appear of potential concern. Legal and illicit substances are commonly detected in the urban air besides waste and surface waters. If nicotine, caffeine and cocaine will result to enough persistence in the air, their monitoring will become an important issue of global chemical watching in the next future.
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